Antistatic fibrous material and method for manufacturing same

ABSTRACT

An antistatic fibrous material manufactured by treating a natural and/or regenerated fibrous material with both (1) at least one di-halogeno-s-triazine that has at least one hydrophilic group, and (2) urea, thiourea, and an amino acid, or a combination of two or more of said three compounds. The treatment includes the following steps: (a) saturating a natural and/or regenerated fibrous material with a solution that contains (1) a di-halogeno-s-triazine having at least one hydrophilic group and (2) urea, thiourea, and an amino acid, or a combination of two or more of said three compounds (b) heating said saturated material at 30° C.-60° C., and (c) heating said saturated material at 60° C.-90° C.

TECHNICAL FIELD

The present invention relates to an antistatic fibrous material and a method for manufacturing said material by treating a fibrous material with a compound having at least two reactive halogen atoms.

BACKGROUND ART

Natural and regenerated fibrous materials are excellent in view of their texture, moisture-absorbing/releasing properties, and their good warmth-retention ability. These properties are known to be based on hydrophilic groups such as —OH and —NH₂ in their chemical structures, which enables them to retain a high moisture content. However, in spite of their high moisture content, such natural and regenerated fibrous materials are still so poor in electrical conductivity that they are likely to store triboelectricity (electrical charge produced by friction between two objects).

When two different materials are rubbed against each other, one is positively charged electrically (+) and the other is negatively charged electrically (−). Natural fibers such as cotton and regenerated fibers such as rayon are usually positively charged by friction, because they are positioned more positively high in the triboelectric series. Furthermore, because fibrous materials are electrically nonconductive, a large amount of electricity that is generated by friction is stored in such materials, and typically little of that is released. In fact, such storage of triboelectricity is sometimes hazardous to human life.

One of the most popular methods for controlling the static electricity of fibrous materials is by coating them with resin-type chemicals that contain antistatic agents and/or electrically conductive materials, so as to modify a material's surface properties. This type of chemical function helps first in lowering the friction coefficient of the surface of a fibrous material, and second in releasing the electricity from the material's surface, due to the high conductivity of the chemical coating.

However, these chemical coatings are limited in their durability, because the thin coating of the chemicals on the surface is easily deteriorated by such environmental factors as oxygen and sunlight, as well as by the friction that occurs when the material is rubbed against another object. Another problem of resin-type chemical coatings is that their adhesive property tends to cause dust and other dirt particles to adhere to the surface of the treated fibrous material, further increasing the material's friction coefficient and causing the material to lose its antistatic effect, in spite of increasing the electrical conductivity of the material. In addition, sometimes a resin-type chemical hardens the treated fibrous material, causing it to lose its soft texture.

As a resin-type chemical treatment, a silicon-based or fluorine-based water-repellent agent has been proposed, but it is usually highly charged with voltage due to friction, thereby posing a potential safety problem. For example, when people who wear work uniforms made of such cloth work at a place, such as a gas station, where flammable substances are handled, there is a risk of ignition or explosion caused by the discharge of electricity from the clothing, even if the electrical charge is slight. Also, the frictional electricity on a work uniform that is made of such cloth causes dirt to adhere on the surface of the uniform, so that such cloth is unsuitable for uniforms in various industries, especially information technology and precision processing industries.

Prior-art disclosures of antistatic agents include a cation polymer in combination with a guanidine salt and/or an inorganic salt [Japanese Unexamined Published Patent Application No. S61-69884], an aminophosphate-type phosphoric ester in combination with a guanidine salt [Japanese Examined Published Patent Application No. S61-58592], a compound having a specific vapor pressure in combination with a quaternary ammonium salt-type cation detergent and aminophosphate-type phosphoric ester [Japanese Unexamined Published Patent Application No. 2002-054072], and a polyester resin having a tertiary amine or quaternary ammonium salt structure [Japanese Unexamined Published Patent Document No. 2003-073657].

Also, there has been proposed wrinkle-free finishing of fibrous materials using dichlortriazines [Japanese Patent No. 3366000], but static control of fibrous materials with dichlortriazines has not been known.

The foregoing indicates that a toxic-free and easily applicable static-control method for natural and regenerated fibrous materials is wanted in the market.

Accordingly, one general object of the present invention is to provide novel antistatic natural and/or regenerated fibrous materials that are less electrically charged by friction, that can easily release the charge that is stored on the material's surface, has an improved texture, has a greater durability against washing, and has little toxicity.

Another object of the present invention to provide a method of manufacturing natural and/or regenerated fibrous materials such as those mentioned above.

DISCLOSURE OF THE INVENTION

The present invention relates to antistatic fibrous materials manufactured by treating a natural and/or regenerated fibrous material with both (1) at least one di-halogeno-s-triazine that has at least one hydrophilic group, and (2) urea, thiourea, or an amino acid, or a combination of two or more of said three compounds.

The treatment includes the following steps: (a) saturating a natural or regenerated fibrous material with a solution that contains a di-halogeno-s-triazine that has (1) at least one hydrophilic group, and (2) urea, thiourea, or an amino acid, or a combination of two or more of said three compounds, (b) heating said saturated material at 30° C.-60° C., and (c) heating said saturated material at 60° C.-90° C.

In another embodiment, the treatment includes the following steps: (a) saturating a natural and/or regenerated fibrous material with a first solution that contains at least one di-halogeno-s-triazine that has at least one hydrophilic group, (b) heating said saturated material at 30° C.-60° C., and (c) saturating said fibrous material with a second solution that contains urea, thiourea, or an amino acid, or a combination of two or more of said three compounds, and (d) heating said saturated material at 60° C.-90° C.

BEST MODE FOR CARRYING OUT THE INVENTION

This invention relates to antistatic fibrous materials manufactured by treating natural and/or regenerated fibrous materials with both (1) at least one di-halogeno-s-triazine that has at least one hydrophilic group, and (2) urea, thiourea, or an amino acid.

The natural and/or regenerated fibrous materials according to this invention include silk, wool, cotton, linen, viscose rayon, Cuprammonium-Rayon, lyocell, Tencel, mixtures of the preceding materials, and mixtures of said materials with other kinds of fibers, including synthetic fibers.

The natural and/or regenerated fibrous materials of this invention also include any form of fibrous product, including: staple-fiber, filament, thread, textile, and non-woven cloth, as well as cloth used for clothing such as work uniforms, shirts, trousers, underclothes such as shorts, brassieres, and other underwear, pajamas, and gloves and socks; interior-decor materials such as curtains, carpets, cover cloths, and tablecloths, and bed items such as sheets, quilt covers, and pillow cases; and industrial goods such as filters and sheets.

The antistatic fibrous materials according to the present invention are manufactured by treating natural and/or regenerated fibrous materials with chemicals that contains (1) at least one di-halogeno-s-triazine that has at least one hydrophilic group (Component A), and (2) urea, thiourea, or an amino acid, or a combination of two or more of said three compounds (Component B).

As Component A, at least one di-halogeno-s-triazine that has at least one hydrophilic group is selected. The di-halogeno-s-triazines having at least one hydrophilic group are, preferably, water-soluble 2,6-dihalogeno-4-Y-1,3,5-triazine expressed by the general formula (1) below, wherein X is a halogen atom selected from Br, Cl, and F, and Y is —OM [wherein M is selected from Na, K, Li, and Mg], or arylamino, aryloxy, arylmercapto, alkylamino, alkoxy, alkylthio, triazinilamino, triaziniloxy, or triazinilthio, and that has at least one group selected from —SO₃M, COOM, —OM, or —SM [wherein M is selected from Na, K, Li, and Mg].

Examples of 2,6-dihalogeno-4-Y-1,3,5-triazine are:

-   2,6-dichlor-4-(3-sulfoanilino)-s-triazine, -   2,6-dichlor-4-(4-sulfoanilino)-s-triazine, -   2,6-dichlor-4-(2,5-disulfoanilino)-s-triazine, -   2,6-dichlor-4-(3,5-disulfoanilino)-s-triazine, -   2,6-dichlor-4-(4-carboxyanilino)-s-triazine, -   2,6-dichlor-4-(3-carboxyanilino)-s-triazine, -   2,6-dichlor-4-(2-carboxyanilino)-s-triazine, -   2,6-dichlor-4-(b-carboxyethylanilino)-s-triazine, -   2,6-dichlor-4-(ureide)-s-triazine, -   2,6-dichlor-4-(thioureide)-s-triazine, -   2,6-dichlor-4-(4-carboxyphenoxy)-s-triazine, -   2,6-dichlor-4-(4-carboxyphenylthio)-s-triazine, -   2,6-dichlor-4-hydroxy-s-triazine Na salt, -   2,6-dichlor-4-hydroxy-s-triazine Li salt, -   2,6-dichlor-4-hydroxy-s-triazine Mg salt, -   2,6-dichlor-4-thio-s-triazine Na salt, and -   2,6-dichlor-4-(3-hydroxyphenyloxy)-s-triazine.

Other than the above-mentioned 2,6-dihalogeno-4-Y-1,3,5-triazines, there are many other di-halogeno-s-triazine compounds that might be effectively applied. The essential factor to be considered in regard to the present invention is that one molecule of each of these compounds has two or more reactive halogen atoms and at least one hydrophilic group. The present invention, therefore, is not be limited by the above-mentioned chemicals.

The method for manufacturing a 2,6-dihalogeno-4-Y-1,3,5-triazine is described, for example, in Germany Patent Official Gazette No. 2357252 and in U.S. Patent Official Gazette No. 5601971.

For example, a trihalogeno-s-triazine is dissolved in 5-50 times its own weight of a water-soluble solvent, to which an aqueous solution of a compound that has a group that reacts with an active halogen, such as —NH₂, —OH, or —SH, and at least one hydrophilic group, is dropwise added at 0° C.-30° C. While said aqueous solution is being added, the mixture is kept slightly alkaline, at pH 8-9, by simultaneous addition of an aqueous solution of an acid scavenger, such as sodium carbonate, sodium bicarbonate, sodium phosphate, sodium hydroxide, or potassium hydroxide.

Also, trihalogeno-s-triazine is hydrolyzed with an alkali, such as sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, or magnesium hydroxide, at a temperature of 0° C.-30° C., so as to produce a di-halogeno-hydroxy-s-triazine metallic salt.

As the aforementioned Component B, at least one compound is selected from urea, thiourea, or an amino acid.

One way to manufacture the antistatic fibrous materials of this invention is to treat a natural and/or regenerated fibrous material with both Component A and Component B. This is achieved by the following steps: (1) saturating a natural and/or regenerated fibrous material in a solution that contains Component A and Component B, and (2) heating said saturated material at 30° C.-60° C., and (3) then heating said saturated material at 60° C.-90° C.

Alternatively, this can be achieved by the following steps: (1) saturating a natural and/or regenerated fibrous material in a first solution that contains Component A, (2) heating the first solution with the material therein at 30° C.-60° C., (3) saturating the material after the preceding step in a second solution that contains Component B, and (4) heating the second solution with the material therein at 60° C.-90° C. The ratio of Component A and Component B by weight must be in the range of 1: (0.1-1.0), preferably in the range of 1: (0.3-0.7).

The methods for saturating a natural and/or regenerated fibrous material with a solution that contains either or both Component A and Component B include a dipping method and a padding method, though the method is not limited to those two methods. In any method, the first step is to prepare an aqueous solution that contains Component A and/or Component B.

An aqueous solution of Component A is prepared with a bath ratio of 1: (2-30), so as to contain an active concentration of 0.5%-10.0% o.w.f. (on the weight of fiber), and an aqueous solution of an alkaline agent such as sodium carbonate, sodium bicarbonate, or sodium hydroxide is prepared so as to become 1.0%-30.0% o.w.f. Otherwise, an acid aqueous solution of acetic acid, glacial acetic acid, malic acid, or citric acid is prepared so as to become 0.1%-5.0% o.w.f.

When both Component A and Component B are used in the same step, Component A and Component B are mixed in an appropriate ratio in water. During this procedure the solution should be kept at a temperature of not more than 30° C. If the temperature of the solution is more than 30° C., the di-halogeno-s-triazine in Component A is hydrolyzed and the activity necessary for attaining the purpose of the invention is lost. If Component A or Component B is used separately from the other component, both of the components are independently solubilized in water in a way similar to that mentioned above.

In the case of a dipping method, a natural and/or regenerated fibrous material is dipped in a solution of Component A and Component B or a solution of Component A in a bath. While circulating the solution or the fibrous material, the bath is kept, as the first step, at 30° C.-60° C. for 1 min.-1 hr., preferably for 2 min.-30 min., and then, as the second step, at 60° C.-90° C. for 2 min.-2 hrs., preferably for 3 min.-1 hr.

In an alternative method, fibrous materials are dipped in a bath that contains a solution of Component A. While circulating the solution or the fibrous material, the bath is kept, as the first step, at 30° C.-60° C. for 1 min.-1 hr., preferably 2 min.-30 min. Then the treated fibrous material is dipped in a bath that contains a solution of Component B at 60° C.-90° C. for 2 min.-2 hrs., preferably for 3 min.-1 hr. After the first step, the fibrous materials can be taken out of the bath to be lightly squeezed and then dipped in the second solution, which contains Component B.

In the case of a padding method, a natural and/or regenerated fibrous material is padded with a solution of Component A and Component B and squeezed until the fibrous material contains 20%-300% of the solution. Or the separate operations of padding and squeezing can be carried out with a solution of Component A and subsequently with a solution of Component B.

If necessary, the operation of padding and squeezing can be repeated for the purpose of increasing the amount of each Component A and Component B that is applied to the fibrous material. Repeating the padding and the drying several times likely will lead to a good result.

After the squeezed fibrous material has been dried, it can be kept, as the first step, at 30° C.-60° C. for 1 min.-1 hr., preferably for 2 min.-30 min., and then kept, as the second step, at 60° C.-90° C. for 2 min.-2 hrs., preferably for 3 min.-1 hr.

If Component A and Component B are treated separately, the fibrous material is padded with a solution of Component A, squeezed and kept at 30° C.-60° C. for 1 min.-1 hr., preferably for 2 min.-30 min. Then the treated fibrous material is padded again with a solution of Component B, then squeezed and kept at 60° C.-90° C. for 2 min.-2 hrs., preferably for 3 min.-1 hr. After the heat treatment, the fibrous material is soaped and then rinsed with water.

By the above-mentioned heat treatment, some halogen atoms in Component A react with —OH or —NH₂ in the fibrous material so as to make a stable bond between Component A and the fibrous material. In other words, the fibrous material contains some hydrophilic Component A that is chemically bonded therein, which helps in controlling static. Component B of this invention promotes the formation of a bond between Component A and the fibrous material.

The process conditions described above are only examples intended to explain this invention, and they can be freely changed depending on the type of fibrous material or other factors.

The present invention provides improved antistatic fibrous materials, especially improved antistatic natural or regenerated fibrous materials. The antistatic fibrous materials store only low levels of electricity caused by spontaneous static induction even if the material is electrically charged due to friction. In addition, the antistatic performance is stable for a long time even after the material is subject to friction. Also, due to the material's ability to retain a high amount of moisture, a wearer feels warm and comfortable.

The present invention will now be further explained by use of the following examples, although its embodiments are not limited to these examples.

Example 1

The following were added to 72 kg of water that was maintained at 10° C.: 26 kg of 10% 2,6-dichlor-4-(3-sulfoanilino)-s-triazine aqueous solution, 1,620 g of sodium bicarbonate, 2,700 g of Na2SO4 10H2O, and 1,080 g of urea. Poplin cloth of 100% cotton was dipped in this solution and squeezed with a mangle so as to make the cloth contain 60% of the solution.

The cloth was kept at 50° C. for 20 min. under a condition of 100% humidity, and then at 85° C. under the same humidity condition for another 20 min. The cloth was then soaped in hot water (80° C.) for 10 min., then rinsed with water, and then dried in dry air of 100° C.

An evaluation of the antistatic properties of this cloth was conducted using (1) a dry cloth (“dry”), (2) a cloth conditioned at 20° C. and 65% relative humidity (hereinafter “RH”) for 24 hours (“conditioned”), and a cloth that was dry-cleaned once with a petroleum solvent (“dry-cleaned”). The results of the evaluation are shown by Table 1.

The triboelectric voltage was measured by a Rotary Static Tester RST-301 (trade name) made by Koa Shokai Co., and the electric charge was measured by an Oscilloscope CO-1305 (trade name) made by Kenwood TMI Co.

Companion Example 1

The same kind of cloths were treated in water in a way similar to the cloths in Example 1, but without any chemicals being added to the water.

TABLE 1 Type of Cloth Example 1 Comparison Example 1 triboelectric voltage Dry 260 1,450 (V) Conditioned 960 1,680 Dry-cleaned 390 2,620 Electric charge Dry − + Conditioned − + Dry-cleaned + to − +

Example 2

The following were added to 162 kg of water maintained at 10° C.: 18 kg of 10% 2,6-dichlor-4-oxy-s-triazine Na salt aqueous solution, 900 g of silk amino acids, 4,500 g of NaHCO3, and 5,400 g of Na2SO4 10H2O. The solution was poured in the bath of a jig-dyeing machine, in which rayon lyocell knit cloth was processed. The bath was kept rotating for 10 min. at 45° C., and then for 30 min. at 70° C. After the water was discharged, the knit cloth was soaped, then rinsed with water, and then dried. The half period of the triboelectric voltage and the differences (%) in the cloths' respective abilities to retain moisture were measured. The results of the evaluation are shown by Table 2.

The half-period of the fiction-charged voltage [time (seconds) required for halving the triboelectric voltage] was measured based on JIS. L 1094 (20° C., RH 40%) by a Static Honestmeter H-0110 (trade name) made by Shishido Shokai Co.

The differences (%) in the cloths' respective abilities to retain moisture (ΔMR) were calculated by the following equation, using 1 g of the treated knit cloth preliminarily dried for 30 min. at 60° C. in a hot-air drying machine:

Wherein

-   -   W1: weight of the sample that was placed for 24 hrs. under the         conditions of temperature, 20° C.; RH, 65%; and wind speed of         about 1 m/min.     -   W2: weight of the sample that was placed for 24 hrs. under the         conditions of temperature 30° C.; RH, 65%; and wind speed of         about 1 m/min.     -   W3: weight of the sample that was placed for 2 hrs. under the         absolute dry condition of 105 (±2)° C.

${\Delta \; {MR}} = {\left( {\frac{w_{1} - w_{3}}{w_{3}} - \frac{w_{2} - w_{3}}{w_{3}}} \right) \times 100}$

Comparison Example 2

The same types of cloths were treated in water in a way similar to the cloths in Example 2 but without any chemicals being added to the water.

TABLE 2 Comparison Type of Cloth Example 2 Example 2 triboelectric Half-period Dry 3 >60 voltage (V) (seconds) Conditioned 20 >60 Dry-cleaned 3 50 Size of waves Dry small large on oscilloscope Conditioned medium large Dry-cleaned small large ΔMR 4.3 3.8

Table 2 shows that the AMR in Example 2 is larger than that of Comparison Example 2, which means that a larger amount of moisture has been retained.

Example 3

The following were added to 252 kg of water maintained at 10° C.: 18 kg of 10% 2,6-dichlor-4-(4-sulfoanilino)-s-triazine aqueous solution, 540 g of acetic acid, and 1,350 g of thiourea. The solution was poured in a bath of a jet dyeing machine, in which woven fabric of 100% silk was processed.

The bath was raised to a temperature of 50° C. at a rate of 2° C./min., and kept at 50° C. for 10 min., then raised to 75° C. and kept at 75° C. for 20 min. After the water was discharged, the fabric was soaped, then rinsed with water, and then dried.

The triboelectric voltage and the half-period of the triboelectric voltage [JIS. L1094 (temperature, 20° C.; RH, 40%)] of the woven fabric were measured. The results of the evaluation are shown by Table 3.

Comparison Example 3

The same kind of cloths were treated in water in a way similar to the cloths in Example 3, but without any chemicals being added to the water.

TABLE 3 Type of Cloth Example 3 Comparison Example 3 triboelectric voltage Dry 600 5,200 (V) Conditioned 1,240 4,600 Dry-cleaned 600 3,800 Half-period of the Dry 6   120< triboelectric voltage Conditioned 12   120< (seconds) Dry-cleaned 24   120<

As can be seen from Table 1, the triboelectric voltage of Example 1 was significantly less than in than Comparison Example 1, and the electric charge of Example 1 was minus (−).

As can be seen from Table 2, the triboelectric voltage of Example 2 was halved for a few seconds, and the difference in moisture-retention(ΔMR %) of Example 2 were better than that of Comparison Example 2.

As can be seen from Table 3, the antistatic effects of Example 3 were better than those of Comparison Example 3. 

1. An antistatic fibrous material manufactured by treating a natural and/or regenerated fibrous material with both (1) at least one di-halogeno-s-triazine that has at least one hydrophilic group, and (2 urea, thiourea, and an amino acid, or a combination of two or more of said three compounds.
 2. An antistatic fibrous material of claim 1, but wherein said treatment includes the following subsequent steps; a) Saturating a natural and/or regenerated fibrous material with a solution that contains (1) a di-halogeno-s-triazine having at least one hydrophilic group and (2) urea, thiourea, and an amino acid, or a combination of two or more of said three compounds; b) Heating said saturated material at 30° C.-60° C.; and c) Heating said saturated material at 60° C.-90° C.
 3. An antistatic fibrous material of claim 1, but wherein said treating includes the following subsequent steps; a) Saturating a natural and/or regenerated fibrous material with a first solution that contains at least one di-halogeno-s-triazine that has at least one hydrophilic group; b) Heating said saturated material at 30° C.-60° C.; c) Saturating the natural and/or regenerated fibrous material with a second solution that contains urea, thiourea, and an amino acid, or a combination of two or more of said three compounds, d) Heating said second saturated material at 60° C.-90° C.
 4. An antistatic fibrous material of claim 1, but wherein said di-halogeno-s-triazine is 2,6-dihalogeno-4-Y-1,3,5-triazine of the formula (1) [but wherein X is a halogen atom selected from Cl, Br, or F]; and Y is —OM [but wherein M is selected from Na, K, Li, and Mg], or arylamino, aryloxy, arylmercapto, alkylamino, alkoxy, alkylthio, triazinilamino, triaziniloxy, or triazinilthio that has at least one substitute selected from —SO₃M, —COOM, —OM, or —SM [but wherein M is selected from Na, K, Li, and Mg].


5. An antistatic fibrous material of claim 3, but wherein said 2,6-dihalogeno-4-Y-1,3,5-triazine is 2,6-dichloro-4-Y-1,3,5-triazine.
 6. An antistatic fibrous material of claim 1, but wherein said natural and/or regenerated fibrous material is silk, wool, cotton, linen, viscose rayon, Cuprammonium-Rayon, lyocell, or Tencel, or any two or more of said materials.
 7. An antistatic fibrous material of claim 1, but wherein said natural and/or regenerated fibrous material is in the form of a staple fiber, filament, thread, textile, or nonwoven cloth. 